Something may be wrong

So this may sound a but strange here goes, I'm on my period btw, but I was on the toilet like 2hrs/ 3hrs ago having a poo and I felt a kind of tearing/ ripping sensation in what I think was my uterus. And as I was wiping that area I noticed the blood was lighter red than it usually is rather than darker. After being on the toilet my uterus started to hurt so I took an ibuprofen like an hour after it started hurting. I was still in pain after taking it. I've just been to the toilet now to pee and it was slightly painful and normally it doesn't hurt to pee when I'm on my period. I don't know how to describe the sensation now but it just kinda hurts. I don't know if it's a serious problem. Does anyone know what's happening or what I should do?